Daisuke Taniguchi of the University of Tokyo in Japan and his colleagues have accurately measured the temperature of the photosphere of red supergiants for the first time.
Red supergiants are the brightest, shortest-lived, and largest stars in the universe. They usually explode like a supernova at the end of their lives, but astronomers cannot yet predict exactly when this will happen.
This is due to the fact that until recently, scientists could not determine the exact temperature of the photosphere of these stars – the lower layer of their atmosphere, in which most of the star’s radiation is formed.
To measure the temperature of a red supergiant, it is necessary to find clearly visible areas of the star’s photosphere, the emission spectrum of which was not influenced by the upper layers of their atmosphere. In addition, there is no one specific absorption line that would unambiguously indicate the surface temperature of such stars.Daisuke Taniguchi, Fellow, University of Tokyo
Thus, astronomers have determined the temperature of the photosphere of ten nearby red supergiants with an accuracy of 30-70 kelvin. In particular, for Betelgeuse it is 3344.85 degrees Celsius, which is about 1.68 times less than the temperature of the Sun’s photosphere.
These latest changes, astrophysicists are sure, will help to understand what processes occur in the bowels of such luminaries, as well as make the first full-fledged predictions on how close Betelgeuse is to becoming a supernova.